The present invention relates to a suspension of a head assembly, a head assembly having the suspension and a method of manufacturing the suspension.
A conventional magnetic disk drive unit, which has been disclosed in Japanese Patent Kokai Gazette No. 6-215513, is shown in FIG. 8. In the disk drive unit 100, a magnetic disk 104 and an actuator 106 for positioning a magnetic head are assembled in an enclosure 102. A base end section of a head assembly 112 is held by an arm 108, which is driven by the actuator 106. The head assembly 112 includes: a suspension 110, which is made of a thin metal plate; and a head slider 10 (see FIG. 9), which is attached to a front end section of the suspension 110.
The suspension 110 and the head slider 10 are shown in FIG. 9 (enlarged view). The suspension 110 includes: a suspension proper 110a whose base end section is attached to the arm 108; and a gimbal section 110b, which is provided to a front end section of the suspension proper 110a. The gimbal section 110b has a U-shaped slit hole 114. A mount section 116, on which the head slider 10 will be mounted, is formed in the slit hole 114. The head slider 10 is adhered on the mount section 116 with an adhesive. Terminals 118 will be connected with electrodes of the head slider 10 by gold balls.
Cable patterns 120 are formed on a surface of the suspension 110, but they are electrically insulated from a base member (a base material) of the suspension 110. The suspension 110 on which the cable patterns 120 are formed is called "CAPS (Cable Patterned Suspension)".
Recently, memory capacity of magnetic disks are becoming greater, and memory density thereof is becoming higher. Thus, smaller magnetic heads have been required. Countermeasures to static electricity have been taken so as to protect semiconductor elements. Since the smaller magnetic heads are employed, further countermeasures to the static electricity are required now.
When a magnetic disk is rotated and rubbed with a magnetic head while conveying a magnetic disk drive unit, the static electricity is generated in the magnetic head. When magnetic heads, which are conveyed as parts of magnetic disk drive units, are rubbed with each other, the static electricity is generated in the magnetic heads, too.
As described above, the head slider 10 is adhered on the mount section 116 with the adhesive. To prevent deformation of the head slider 10, a non-electro-conductive adhesive having small Young's modulus is employed as the adhesive. A conventional countermeasure to the static electricity in the magnetic head includes: adhering the head slider 10 on a mount section 116 with the non-electro-conductive adhesive; electrically connecting the head slider 10 with the suspension 110 with an electro-conductive adhesive; and discharging the static electricity to the suspension 110. The adhesive strength of the electro-conductive adhesive is less than that of the non-electro-conductive adhesive, but the head slider 10 is required to be securely and reliably adhered on the suspension 110 with the non-electro-conductive adhesive having greater adhesive strength, so that the electro-conductive adhesive and the non-electro-conductive adhesive are used.
FIG. 10 is a sectional view of the cable patterns 120 formed on the surface of the suspension 110. The cable patterns 120 are electrically insulated from the base member of the suspension by an insulating layer 130. And surfaces of the cable patterns 120 are protected by another insulating layer 132.
A surface of the mount section 116 is coated with an insulating layer as in as the structure shown in FIG. 10. On the other hand, a metal surface is exposed in an adhering area of the mount section 116, in which the head slider 10 will be adhered, so the head slider 10 and the suspension 110 can be electrically connected by applying the electro-conductive adhesive between the metal surface and the head slider 10.
In the conventional disk drive unit, the head slider 10 must be attached to the mount section 116 by the troublesome two steps of: adhering the head slider 10 on the mount section 116 with the non-electro-conductive adhesive; and applying the adhesive.